Conventional ball nut and screw assemblies are normally designed with a helical ball raceway formed by mating helical grooves whose sides but not their bottom contact the balls to react load axially through the centerline of the assembly. While thus well adapted to reacting the axial loading, a simultaneous radial or side load on the ball nut places an extreme burden on the raceway greatly reducing the load carrying capacity and useful life of the ball nut.
Examples of various ball nut and screw assemblies are disclosed in U.S. Pat. Nos. 2,298,011; 4,221,137 and 4,557,156. As can be gathered from their ball groove configurations, they may be well adapted for axial loading but not radial loading.